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    <title>find_freq</title>
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    <center>Scilab Function</center>
    <div align="right">Last update : April 1993</div>
    <p>
      <b>find_freq</b> -  parameter compatibility for elliptic filter design</p>
    <h3>
      <font color="blue">Calling Sequence</font>
    </h3>
    <dl>
      <dd>
        <tt>[m]=find_freq(epsilon,A,n)  </tt>
      </dd>
    </dl>
    <h3>
      <font color="blue">Parameters</font>
    </h3>
    <ul>
      <li>
        <tt>
          <b>epsilon</b>
        </tt>: passband ripple</li>
      <li>
        <tt>
          <b>A</b>
        </tt>: stopband attenuation</li>
      <li>
        <tt>
          <b>n</b>
        </tt>: filter order</li>
      <li>
        <tt>
          <b>m</b>
        </tt>: frequency needed for construction of elliptic filter</li>
    </ul>
    <h3>
      <font color="blue">Description</font>
    </h3>
    <p>
    Search for m such that <tt>
        <b>n=K(1-m1)K(m)/(K(m1)K(1-m))</b>
      </tt>
    with</p>
    <p>
      <tt>
        <b>m1=(epsilon*epsilon)/(A*A-1)</b>
      </tt>;</p>
    <p>
    If <tt>
        <b>m = omegar^2/omegac^2</b>
      </tt>, the parameters
    <tt>
        <b>epsilon,A,omegac,omegar</b>
      </tt> and <tt>
        <b>n</b>
      </tt> are then
    compatible for defining a prototype elliptic filter.
    Here, <tt>
        <b>K=%k(m)</b>
      </tt> is the complete elliptic integral with parameter <tt>
        <b>m</b>
      </tt>.</p>
    <h3>
      <font color="blue">See Also</font>
    </h3>
    <p>
      <a href="percentk.htm">
        <tt>
          <b>%k</b>
        </tt>
      </a>,&nbsp;&nbsp;</p>
    <h3>
      <font color="blue">Author</font>
    </h3>
    <p>F. D.  </p>
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